Flat Linear Vibrator

ABSTRACT

A linear vibrator is disclosed. The linear vibrator includes a housing having a base and a cover, a number of elastic members connected to the housing, a vibrating unit suspended in the housing by the elastic members, and a coil positioned in the housing. The base has a bottom wall and a plurality of sidewalls extending vertically from the bottom wall. The vibrating unit has a magnet assembly and vibrates along a direction parallel to the bottom wall. The base further has a block located on the bottom wall. The block is located on a vibration path of the weight contacting the weight during vibration. An effective elastic displacement of the elastic member is not smaller than a distance between the block and a part contacting the block of the weight.

FIELD OF THE INVENTION

The present invention generally relates to the art of vibrators and,more particularly, to a flat linear vibrator for generating tactilesensation.

DESCRIPTION OF RELATED ART

Consumer products, such as mobile phones and portable multi-mediaplayers, generally include vibrators for generating tactile feedback.For example, a mobile phone has a vibrator for generating vibrationwhile a call is called in, and a portable multi-media player has a touchscreen having vibrators for getting tactile feedback.

A vibrator has a moving unit moving along a linear direction is calledlinear vibrator. Linear vibrators are widely used in consumer productsand are disclosed in U.S. Pat. No. 6,466,682 B2 issued on Oct. 15, 2002,and U.S. Pat. No. 7,099,489 B2 issued on Aug. 29, 2006. The vibrator ismounted on a mounting surface of a printed circuit board, and the movingunit thereof is actuated to move along a direction perpendicular to themounting surface. However, the movement along the directionperpendicular to the mounting surface increases the height of thevibrator.

So, it is necessary to provide a new vibrator for solving the problemmentioned above.

SUMMARY OF THE INVENTION

In one embodiment of the present invention, a linear vibrator isdisclosed. The linear vibrator includes a housing having a base and acover, a number of elastic members connected to the housing, a vibratingunit suspended in the housing by the elastic members, and a coilpositioned in the housing. The base has a bottom wall and a plurality ofsidewalls extending vertically from the bottom wall. The vibrating unithas a magnet assembly and vibrates along a direction parallel to thebottom wall. The base defines a pair of blocks for limiting thevibration amplitude of the vibrating unit.

Other features and advantages of the present invention will become moreapparent to those skilled in the art upon examination of the followingdrawings and detailed description of the exemplary embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of a linear vibrator in accordance with anembodiment of the present invention;

FIG. 2 is an exploded view of the linear vibrator in FIG. 1;

FIG. 3 is top view of the linear vibrator, a cover thereof being removedaway;

FIG. 4 is an isometric view of an elastic member of the linear vibrator;

FIG. 5 is a cross-sectional view of the linear vibrator along a line A-Ain FIG. 1; and

FIG. 6 is a schematic illustration showing how the vibrator woks.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENT

Reference will now be made to describe an exemplary embodiment of thepresent invention in detail.

A linear vibrator is mounted on a printed circuit board for generatingtactile vibration. Referring to FIGS. 1-3, a linear vibrator 10, inaccordance with an embodiment of the present invention, includes a cover11, a base 12 forming a receiving space together with the cover 11, anannular coil 13, a plurality of elastic member 14, a weight 15, and amagnet assembly 16. The cover 11 and the base 12 corporately form ahousing having the receiving space. The base 12 further defines a bottomwall 122 and a plurality of sidewalls 121 extending vertically from thebottom wall 122. When the vibrator 10 is mounted on the printed circuitboard 20, the bottom wall 122 is attached and parallel to the printedcircuit board 20.

The coil 13 is positioned on the bottom wall 122 and a pair of leadsthereof is electrically connected to electrical pads embedded in thebottom wall 122 for receiving current from external circuits. Theelastic members 14 are positioned on the base 12, preferably on thesidewalls 121 of the base 12. The weight 15 is suspended in thereceiving space by the elastic members 14. The weight 15 includes a mainbody 151 and a plurality of positioning portions 152 extending from themain body 151. The positioning portions 152 are used for assembling withthe elastic members 14. The main body 151 defines a through hole 153 ina middle portion thereof for receiving the magnet assembly 16 therein.Thus, the magnet assembly 16, together with the weight 15, is suspendedin the receiving space by the elastic members 14. In fact, the magnetassembly 16 may be solely served as a vibrating unit, and may bedirectly connected to the elastic members 14. In addition, if used, theweight 15 can be made from materials having specific gravities higherthan 7.8 g/cm³. The base 12 further defines a block 123 located on thebottom wall 122. The block 123 is located on a vibration path of thevibrating unit in order to contact the vibrating unit for limiting thevibration amplitude of the vibrating unit during vibration. When thevibrating unit is still, an effective elastic displacement of theelastic member 14 is not smaller than a distance between the block 123and a part of the vibrating unit contacting the block 123. The so-calledeffective elastic displacement is defined as a maximum elasticdeformation of the elastic arm 142 along the vibrating direction of thevibrating unit.

Referring to FIGS. 4-5, together with FIGS. 1-3, each of the elasticmembers 14 includes a fastening portion 141 fixed on the sidewall 121,an elastic arm 142 substantially parallel to the fastening portion 141,and a mounting portion 144 extending from the elastic arm 142. Thefastening portion 141 is connected to the elastic arm 142 by a U-shapeconnecting portion 143. Preferably, the fastening portion 141 mayinclude a first fastening part 141 a and a second fastening part 141 bsubstantially perpendicularly to the first fastening part 141 a, bywhich the fastening portion 141 can be positioned on two adjacentsidewalls 121 of the base 12. In order to fast the elastic members 14stably and firmly, the fastening portion 141 further comprises a thirdfastening part 141 c extending from the first fastening part 141 a andlocated on the bottom wall 122. The mounting portion 144 extendsvertically from the elastic arm and extends far away from the fasteningportion 141. Further, preferably, the mounting portion 144 may includean upper part 144 a, a lower part 144 b opposed from the upper part 144b, and a slot 144 c between the upper part 144 a and the lower part 144b. Accordingly, the elastic arm 142 can deform elastically along adirection X-X substantially perpendicularly to the first fastening part141 a. The positioning portion 152 of the weight 15 is at leastpartially received in the slot 144 c of the mounting portion 144 of theelastic member 14, i.e., the positioning portion 152 is sandwichedbetween the upper part 144 a and the lower part 144 b. Therefore, theweight 15 is suspended in the receiving space by the elastic members 14.

The magnet assembly 16 in the through hole 153 has two halves, in which,one half 16 a has magnetic poles opposite to those of the other half 16b, as shown in FIG. 5. Planes of magnetic poles of the magnet assembly16 are parallel and face to the bottom wall 122 and are also parallel tothe coil 13. The magnet assembly 16 is arranged above the coil 13. Thecoil 13 receives current from external circuit. At one moment, directionof the current passing through the left half of the coil 13 is inwardinto the paper (labeled as {circle around (x)}), and direction of thecurrent passing through the right half of the coil 13 is outward(labeled as ⊙). Magnetic lines of force are shown as dashed lines witharrows. According to Left-hand rule, direction of the electromagneticforce F1 applied on the left half coil 13 is rightward, and direction ofthe electromagnetic force F2 applied on the right half coil 13 is alsorightward. Thus, the whole coil 13 is given a rightward totalelectromagnetic force which forces the coil 13 to move rightward.However, the coil 13 is positioned on the bottom wall 122 and can't moveby the force. As a result, the weight 15 suspended by the elasticmembers 14 is forced to move leftward by the reaction force F′. Asdirection and intensity of the current passing through the coil 13 isvaried, the movement of the weight 15 is leftward or rightward,alternatively, which is called vibration. Direction of the vibration isparallel to the bottom wall 122.

As the direction of vibration is parallel to the bottom wall, a heightof the linear vibrator can be reduced. During vibration, the elasticmembers 14 is constantly and alternatively compressed and stretched. Ifthe vibration amplitude exceeds the maximum elastic deformation of theelastic members, the elastic members may be damaged. By virtue of theblocks, the elastic members are effectively protected from plasticdeformation.

While the present invention has been described with reference to aspecific embodiment, the description of the invention is illustrativeand is not to be construed as limiting the invention. Various ofmodifications to the present invention can be made to the exemplaryembodiment by those skilled in the art without departing from the truespirit and scope of the invention as defined by the appended claims.

1. A linear vibrator, comprising: a cover; a base forming a housingtogether with the cover, the base defining a bottom wall and a pluralityof sidewalls; a plurality of elastic members received in the housing,each of the elastic members including a fastening portion connecting tothe housing, an elastic arm extending from the fastening portion, and amounting portion extending from the elastic arm, the elastic arm beingdeformable parallel to the bottom wall; a weight suspended in thehousing by the elastic members and defining a through hole therein; amagnet assembly accommodated in the through hole of the weight, one halfof the magnet assembly having magnetic poles opposite to those of theother half, and planes of magnetic poles of the magnet assembly beingparallel and facing to the bottom wall of the base; and a coilpositioned on the bottom wall and located below the magnet, wherein thebase further defines a block located on the bottom wall, and the blockis located on a vibration path of the weight for contacting the weightduring vibration, and an effective elastic displacement of the elasticmember is not smaller than a distance between the block and a part ofthe weight contacting the block of the weight while the weight is still.2. The linear vibrator as described in claim 1, wherein the fasteningportion of the elastic member includes a first fastening part connectingto one sidewall of the base and a second fastening part connecting toanother adjacent sidewall.
 3. The linear vibrator as described in claim1, wherein the mounting portion of the elastic member includes an upperpart, a lower part opposed from the upper part, and a slot between theupper part and the lower part.
 4. The linear vibrator as described inclaim 3, wherein the weight defines a positioning portion at leastpartially received in the slot and sandwiched between the upper part andthe lower part.
 5. The linear vibrator as described in claim 1, wherein,the weight is made from materials having specific gravities higher than7.8 g/cm³.
 6. A linear vibrator, comprising: a housing including a coverand a base, the base defining a bottom wall and a plurality of sidewallsvertically extending from the bottom wall; a plurality of elasticmembers connected to the housing, each of the elastic members includingan elastic arm being deformable parallel to the bottom wall; a vibratingunit suspended by the elastic members, the vibrating unit comprising amagnet assembly, one half of the magnet assembly having magnetic polesopposite to those of the other half, and planes of magnetic poles of themagnet assembly being parallel and facing to the bottom wall of thebase; and a coil positioned on the bottom wall and located below themagnet, wherein the base further defines a block located on the bottomwall, and the block is located on a vibration path of the weight forcontacting the weight during vibration, and an effective elasticdisplacement of the elastic member is not smaller than a distancebetween the block and a part of the weight contacting the block of theweight while the weight is still.
 7. The linear vibrator as described inclaim 6, wherein the elastic member further including a fasteningportion having a first fastening part connecting to one sidewall of thebase and a second fastening part connecting to another adjacentsidewall.
 8. The linear vibrator as described in claim 7, wherein theelastic member further defines a mounting portion extending from theelastic arm, the mounting portion including an upper part, a lower partopposed from the upper part, and a slot between the upper part and thelower part.
 9. The linear vibrator as described in claim 8, wherein theweight defines a positioning portion at least partially received in theslot and sandwiched between the upper part and the lower part.
 10. Thelinear vibrator as described in claim 6 further comprising a weightwhich is made from materials having specific gravities higher than 7.8g/cm³.
 11. A linear vibrator, comprising: a housing including a base anda cover, the base having a bottom wall and a plurality of sidewallsextending vertically from the bottom wall; a plurality of elasticmembers connected to the housing; a vibrating unit suspended in thehousing by the elastic members, the vibrating unit having a magnetassembly and vibrating along a direction parallel to the bottom wall; acoil positioned on the bottom wall and facing the magnet assembly,wherein the base further defines a block located on the bottom wall, andthe block is located on a vibration path of the vibrating unit forcontacting the vibrating unit during vibration, and an effective elasticdisplacement of the elastic member is not smaller than a distancebetween the block and a part of the vibrating unit contacting the blockof the weight while the vibrating unit is still.
 12. The linear vibratoras described in claim 11 further comprising a weight surrounding themagnet assembly, the weight being made from materials having specificgravities higher than 7.8 g/cm³.